Abstract： Objective： To investigate the effect of panax notoginseng saponins on the water maze behavior of gene knockout mice with fragile X syndrome. Methods：Gene knockout mice with fragile X syndrome were randomly divided into the wild- type(WT) group， the knockout(KO) group and the treatment group. In the treatment group， 30 mg/kg panax notoginseng saponins were used to treat gene knockout mice with fragile X syndrome. The Morris Water Maze Experiment was used to test the spatial memory ability of mice. The experiment lasted for four days， and the incubation period and swimming trajectory of each day were recorded. On Day 5，the platform was removed and the percentage of time the mice spent in each quadrant was recorded. Results： During the directional navigation experiment， there was no significant difference in the comparison of the incubation period between the three groups on Day 1 and Day 2(P＞0.05). On Day 3 and day 4，the incubation period in the KO group was increased when compared with that in the WT group(P＜0.05)，and the incubation period in the treatment group was decreased when compared with that in the KO group(P＜0.05). In the spatial search experiment，the number of crossing the platform in the KO group was decreased(P＜0.05) and spent less time in the first quadrant when compared with that in the WT group；the number of crossing the platform in the treatment group was increased and spent more time in the first guadrant when compared with that in the KO group(P＜0.05). Conclusion：KO mice had cognitive dysfunction，and 30 mg/kg of panax notoginseng saponins can improve spatial memory in KO mice.